As a photoelectric conversion device, a solid-state imaging device used in an imaging device such as a camera or the like has been known. The solid-state imaging device includes light-receiving elements (visible-light detection sensor) that detect visible light for every pixel, generate an electric signal corresponding to visible light incident from the outside, and process the electric signal to form a captured image. As the light-receiving element, a CMOS image sensor or a CCD image sensor, which is formed according to a semiconductor process is broadly known.
The above solid-state imaging device blocks light other than visible light, which becomes a noise component, in order to accurately detect an intensity of the visible light incident on the light-receiving element. For example, there is a technology in which before the incident light reaches the light-receiving element, an infrared component is blocked with an infrared cut filter. In this case, since substantially only visible light reaches the light-receiving element, a sensing operation having a relatively low noise component may be realized.
On the other hand, recent years, there is an increasing demand for providing a sensing function such as motion capture or distance cognition (space cognition), which uses a near-infrared light, to the solid-state imaging device. As a technology for this, a study for incorporating a distance image sensor that adopts a TOF (Time Of Flight) method in the solid-state imaging device has been forwarded.
The TOF method is a technology that measures a distance from a light source to an object to be imaged by measuring a time until light output from a light source is reflected by the object to be imaged and returns. For measuring a time, a phase difference of light is used. That is, since a phase difference is generated in the returned light depending on the distance to the object to be imaged, in the TOF method, this phase difference is converted into a time difference, and based on the time difference and a speed of light, the distance up to the object to be imaged is measured for every pixel.
Since the solid-state imaging device that adopts the TOF method like this is necessary to detect an intensity of the visible light and an intensity of the near-infrared light for every pixel, it is necessary for each of the pixels to be provided with a light-receiving element for detecting the visible light and a light-receiving element for detecting the near-infrared light. For example, as an example where the light-receiving element for detecting visible light and the light-receiving element for detecting near-infrared light are provided for every pixel, a technology described in Patent Literature 1 is known.
In the Patent Literature 1, an image sensing device in which an optical filter array containing a dual band pass filter and an infrared pass filter and a pixel array containing a RGB pixel array and a TOF pixel array are combined is disclosed. According to the technology described in the Patent Literature 1, the dual band pass filter allows selective transmission of the visible light and the infrared light, and the infrared pass filter provided only on the TOF pixel array allows transmission of the infrared light. Thus, since the visible light and the infrared light are incident on the RGB pixel array and the infrared light is incident on the TOF pixel array, each pixel array may detect necessary light ray.